Simple, non-invasive technique could benefit patients suffering abdominal aorta aneurysms

Tuesday, 2 November 2010

Researchers at Southmead Hospital in Bristol have been awarded a major grant to investigate the benefits of a simple, non-invasive procedure that could significantly improve the survival rates of patients undergoing aorta aneurysm surgery.

An abdominal aneurysm is an enlarged and weakened section of the abdominal aorta, the main artery that carries blood from the heart. Currently around 7.6 percent of men in the UK have an abdominal aorta aneurysm between the ages of 65 and 80.

As an aneurysm increases in size it can split open, which carries a very high risk of death. Therefore, when it reaches a certain size it is best to repair it surgically before it becomes dangerous.

During this operation the surgeon replaces the weak section in the aorta with a graft.

To do this the surgeon will clamp the artery above and below the aneurysm to prevent blood flowing through the area during surgery.

This situation, when blood flow to an organ is cut off, is called ischaemia. When the blood supply to an organ returns after a period of ischaemia (a process called reperfusion), damage can occur.

The absence of oxygen and nutrients during ischaemia creates a condition in which, the restoration of blood supply results in inflammation and damage to tissues.

Because of this heart and kidney problems and even death after operations on the abdominal aorta are not uncommon. However, research has proved that if the blood supply is first halted for a short time and then restored quite quickly the tissue cells seem to ‘learn’ to deal with later and longer periods of loss of blood flow in a process called ischaemic preconditioning. 

Consultant Anaesthetist Dr Ronelle Mouton and her team have received £207,000 from the National Institute for Health Research (NIHR) to carry out the research.

Dr Mouton said: “There are several experimental laboratory studies and some small clinical trials, which suggest that ischaemic preconditioning may protect the heart and other organs during big operations. 

“In this study we are investigating whether remote ischaemic preconditioning, done in a simple and safe way by inflating a normal blood pressure cuff on the patient’s arm for five minutes, protects the patient and reduces heart and kidney problems after abdominal aneurysm operations. The procedure is repeated three times with five minutes of rest in-between.”

“The direct result of the present study will be the detailed planning for a multi-centre trial of implementation across the full range of NHS units routinely providing this surgery.  

“If the results of the definitive trial are positive, this simple, non-invasive intervention could be introduced across NHS hospitals at very low cost. Furthermore, NHS costs might be reduced by fewer postoperative complications and shorter intensive care and hospital stays.

“Remote ischaemic preconditioning of the kind assessed here also has potential application in other large volume surgical areas with ischaemic intervention, such as heart, neuro and plastic surgery.”